Nutrition: Per serving (8)
First, make the stuffing. Melt the butter in a saucepan over a medium heat, then tip in the onions and sizzle for about 8 mins until golden. Add the garlic and cook for 2 mins more, then turn off the heat and leave to cool. Tip the bread and parsley into a food processor with plenty of seasoning and blitz to crumbs. Scrape in all the buttery onions and pulse to make a bright green stuffing – the ingredients will come together to form a paste. Set aside. Will keep covered in the fridge for up to a day.
Lay the turkey breast out on a board, skin-side down, with the tip of the breast at the top. Butterfly the breast by cutting partway into the thickest side (be careful not to cut all the way through), then opening it out like a book. Cover with a sheet of baking parchment and use a meat mallet or rolling pin to gently bash it out into a rough rectangle – the meat should be an even thickness of about 2cm. Remove the parchment, season and spread the stuffing over the turkey, leaving a small border around the edges. Starting from one of the short sides, roll the turkey breast into a tight log, then tie with kitchen string at even intervals to hold it all together. Will keep covered in the fridge for up to a day.
Heat the oven to 210C/190C fan/gas 6½. Put the turkey roulade seam-side down in a shallow roasting tin or on a rack set in the tin, if you have one. Brush with the melted butter and season. Roast for 40 mins until the skin has crisped up, then brush with the maple syrup and roast for 30-40 mins more, basting occasionally with the juices in the tin until the middle of the roulade reaches 70C on a digital thermometer (check after 30 mins, as oven temperatures vary). Leave to rest for at least 10 mins before carving into thick slices. Use the juices to make a gravy in the tin, if you like, and serve alongside.
